Systemic isosporosis in different species of passerine birds

Systemic isosporosis in different species of passerine birds | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Systemic isosporosis in different species of passerine birds Camila Issa Amaral, Ayisa Rodrigues de Oliveira, Eric Santos Oliveira, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6346858/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Jun, 2025 Read the published version in Veterinary Research Communications → Version 1 posted 14 You are reading this latest preprint version Abstract Systemic isoporosis (atoxoplasmosis) is a disease caused by apicomplexan parasites of the genus Isospora , with systemic distribution due to an extraintestinal part of the cycle. In this report we described the gross and histological lesions of systemic isosporosis in 15 passeriform birds from three different species: Sporophila maximiliani (great-billed seed finch), Serinus canaria (island canary), and Saltator similis (green-winged saltator), all captive birds originating from different properties in Minas Gerais, Brazil. Between 2017 and 2022, 15 passerines were sent to the Veterinary School of the Universidade Federal de Minas Gerais for post mortem examination, as well as fixed tissue samples for histopathological analysis. Histologically, the lamina propria of the small intestine in 13 out of 15 birds showed marked histiocytic and lymphoplasmacytic infiltrates with rare heterophils. Merozoites compatible with Isospora spp. were observed within the cytoplasm of macrophages and extracellularly. Histological changes associated with merozoites were also seen in different organs like liver (9/15), lungs (4/15), heart (3/15), spleen (1/15), and skeletal muscle (1/15). To further characterize the pathogen, DNA was extracted from frozen tissues of one bird ( Saltator similis ), and 23S large subunit ribosomal RNA and cytochrome c oxidase subunit 1 (COI) genes were amplified and sequenced. Systemic isosporosis affects various passerine species; however, this is the first report in Sporophila maximiliani . This study enabled the characterization and description of the histological lesions associated with systemic isosporosis in this species. atoxoplasmosis birds great-billed seed finch histopathology protozoa Figures Figure 1 Figure 2 Figure 3 Introduction Systemic isosporosis, previously referred as atoxoplasmosis, is an infectious disease caused by apicomplexan protozoa of the genus Isospora . These parasites can induce diseases confined to the gastrointestinal system or lead to systemic alterations, causing lesions in multiple organs (Ball 1998; Adkesson et al. 2005 ; Flach et al. 2022 ). This disease has been reported in a wide range of passerine species, including house sparrows ( Passer domesticus ) (Gill et al. 2008), canaries ( Serinus canaria ) (Quiroga et al. 2000 ; Maslin and Latimer 2009 ; Sánchez-Cordón et al. 2007 ), european greenfinches ( Carduelis chloris ) (Cooper et al. 1989 ), rose-breasted grosbeaks ( Pheucticus ludovicianus ) (Khan et al. 1971), Bali mynahs ( Leucopsar rothschildi ) (Partington et al. 1989 ), various finch species (Pennycott et al. 1998 ; Lindstrom et al. 2009 ), different tanager species (Adkesson et al. 2005 ), blue-crowned laughingthrush ( Dryonastes courtoisi ) (Mohr et al. 2017), green-winged saltators ( Saltator similis ) (Oliveira et al. 2018 ), goldfinches (Gosbel et al. 2020), and others. The life cycle of these coccidia has been the subject of experimental and descriptive studies, but remains poorly understood. In summary, the parasite is transmitted via fecal-oral route (Levine 1982 ), and asexual reproduction (merogony) in both enterocytes and macrophages or lymphocytes leads to the dissemination of merozoites to other organs (Adkesson et al. 2005 ). Sexual reproduction (gametogony) occurs in enterocytes, primarily in the duodenum, of the same host. Histopathological analysis showed that various organs, such as the intestine, liver, and spleen, can exhibit inflammatory infiltrates composed of lymphocytes, plasma cells, and macrophages, along with variable amounts of intracellular merozoite aggregates (Maslin and Latimer 2009 ; Sánchez-Cordón et al. 2007 ). The systemic form of isosporosis is a significant cause of mortality in passerines, particularly in young birds and those kept in captivity. Factors such as high population densities and mixed-species aviaries result in increased shedding of infectious oocysts, potentially exacerbating the clinical condition (Rossi et al. 1997 ). This is particularly concerning for rare and endangered species, as well as for birds bred for release into the wild, which may expose threatened free-ranging populations to a novel pathogen (Kubiski et al. 2022 ). This study aimed to report systemic isosporosis causing fatal disease in three different passerine species: great-billed seed finch ( Sporophila maximiliani ), island canary ( Serinus canaria ), and green-winged saltator ( Saltator similis ). Although this disease has been previously documented in a wide range of passerine species, this is the first documented report of systemic isosporosis in great-billed seed finch. While all three reported species face threats from habitat degradation and illegal bird trade in Brazil, only the great-billed seed finch is currently classified as globally endangered by the International Union for Conservation of Nature (IUCN) (BirdLife International, 2017) and critically endangered according to Brazilian authorities (Brasil, 2016 ). This study also aimed to describe the anatomopathological and molecular findings of the disease in passerine species from different locations in Minas Gerais, Brazil. The research highlights the significance of this disease in captive birds and those threatened with extinction. Case presentation Collection history Between 2017 and 2022, 15 passerines were diagnosed with systemic isosporosis through post-mortem examination and histopathology at the Veterinary School ofUniversidade Federal de Minas Gerais. The birds belonged to the following species: great-billed seed finch ( Sporophila maximiliani ) (10/15), island canary ( Serinus canaria ) (4/15), and green-winged saltator ( Saltator similis ) (1/15). All birds died naturally and originated from different breeding facilities located in Minas Gerais, Brazil (Table 1 ). Table 1 Cases of systemic isosporosis received at the Veterinary School of UFMG from 2017 to 2022. Sample ID Received year Species (commom name) Family Farm Age 1 2022 Sporophila maximiliani (great-billed seed finch) Thraupidae A Juvenile 2 2022 Serinus canaria (island canary) Fringillidae B Juvenile 3 2022 Serinus canaria (island canary) Fringillidae B Juvenile 4 2022 Serinus canaria (island canary) Fringillidae B Juvenile 5 2022 Saltator similis (green-winged saltator) Fringillidae C Adult 6 2021 Sporophila maximiliani ( great-billed seed finch) Thraupidae D Adult 7 2021 Sporophila maximiliani ( great-billed seed finch) Thraupidae D Adult 8 2021 Serinus canaria (island canary) Fringillidae D Juvenile 9 2018 Sporophila maximiliani ( great-billed seed finch) Thraupidae E Adult 10 2018 Sporophila maximiliani (great-billed seed finch) Thraupidae E Juvenile 11 2017 Sporophila maximiliani (great-billed seed finch) Thraupidae F Adult 12 2017 Sporophila maximiliani (great-billed seed finch) Thraupidae F Adult 13 2017 Sporophila maximiliani (great-billed seed finch) Thraupidae G Adult 14 2017 Sporophila maximiliani (great-billed seed finch) Thraupidae H Juvenile 15 2017 Sporophila maximiliani (great-billed seed finch) Thraupidae H Adult Clinical presentations Clinical signs were similar across all birds and included inappetence, ruffled plumage, hyporexia, reduced activity, diarrhea, and death. The disease progression ranged from two to ten days, with mortality rates varying between breeding sites from 5–33.3%. All birds were housed in individual cages and fed a diet of mixed seeds and fruits. The canaries in 2, 3 and 4 originated from a farm composed of 15 birds of the same species, with ten adults and five chicks. Four chicks died, and the onset of mortality coincided with the introduction of a new adult bird of the same species to the aviary. For the great-billed seed finches 9–13, only formalin fixed samples of organs (intestine, liver, lungs, heart, and proventriculus) for histopathological examination were received, and no clinical history or epidemiological data were provided. Anatomopathological examination Twelve out of 15 birds were grossly examined, and ten (10/12) presented poor body condition, evidenced by a prominent keel and marked atrophy of pectoral muscles, while two birds displayed good body condition. During necropsy, samples of liver, spleen, pancreas, proventriculus, gizzard, small intestine, large intestine, kidneys, lungs, pectoral muscle, heart and brain were collected, fixed in 10% buffered formalin, subjected to routine processing, embedded in paraffin, sectioned at 4 µm and stained with hematoxylin and eosin (H&E) (Luna, 1968 ). All birds were diagnosed with systemic isosporosis by histopathological examination, with some variations in the affected species and organs. The main lesions associated with the parasite included enteritis, hepatitis, pneumonia, myocarditis, splenitis, and myositis (Fig. 1 ). In great-billed seed finch, the most consistent gross lesions were observed in the duodenum and jejunum, characterized by markedly thickened walls with luminal stenosis (Fig. 2 a). Microscopically, all true finches (10/10) exhibited transmural disorganization of the duodenal and jejunal architecture, with loss of villous structure and replacement of intestinal crypts by intense inflammatory infiltrate (Fig. 2 b), predominantly composed of lymphocytes, with fewer macrophages. In eight birds (8/10), the inflammatory infiltrate occasionally extended beyond the intestinal wall, reaching the serosal surface (Fig. 2 c). In all examined sections, merozoites of Isospora sp. measured 2–3 µm, were round, basophilic, and surrounded by a clear halo. The merozoites were observed within macrophages, lymphocytes, enterocytes, and extracellularly. In four birds (4/10), moderate to marked multifocal to coalescent lymphohistiocytic hepatitis with intralesional merozoites was also noted. In the green-winged saltator, all intestinal segments were distended, with diffuse hyperemia of the serosa with moderate thickening of the duodenal and jejunal walls. On the surface of mucosa there was moderate amount of friable and yellowish material (Fig. 2 d). Histologically, the mucosa and submucosa of the small intestine exhibited circumferential necrosis and marked fibrin deposition, associated with a moderate inflammatory infiltrate composed of lymphocytes and macrophages (Fig. 2 e). Merozoites compatible with Isospora sp. were observed within macrophages and extracellularly (Fig. 2 f). Additionally, lymphocytic and histiocytic hepatitis, myocarditis, splenitis, and myositis were noted, all associated with merozoites compatible with Isospora spp. located inside machophages and lymphocytes, as well as extracellularly. In the canaries, all intestinal segments were distended with diffuse serosal hyperemia, and the lumen was filled with hemorrhagic content. In the liver of one bird (1/4), there were multifocal to coalescing white-yellow friable areas that extended into the parenchyma (Fig. 2 g). The lungs of three canaries (3/4) were non-collapsed, slightly consolidated, and diffusely red. Microscopically, the liver had extensive multifocal areas of necrosis, and marked inflammatory infiltrate (Fig. 2 h) composed of lymphocytes and macrophages associated with Isospora sp. merozoites (Fig. 2 i). Two canaries (2/4) presented lymphocytic and histiocytic pericarditis and myocarditis (Fig. 2 j). with few extracellular Isospora spp. merozoites In the lungs of three birds (3/4), there was marked diffuse interstitial lymphocytic and histiocytic pneumonia (Fig. 2 k) associated with some intra-histiocytic and extracellular Isospora spp. merozoites. Polimerase chain reaction (PCR) and sequencing DNA was extracted from frozen tissue samples (liver, spleen, and intestine) from one case ( Saltator similis , case 5) using the Qiagen DNeasy Kit (Valencia, California, USA) as recommended by the manufacturer. Polymerase chain reaction (PCR) was used to amplify a 1,495 bp portion (Mugridge et al. 2000 ; Schrenzel et al. 2005 ; Oliveira et al. 2018 ) of the large chromosomal ribosomal RNA subunit of the 23S gene (23S rRNA). For reaction, 0.2 µM of each oligonucleotide named 23S-F 5'-TACCCGCTGAACTTAAGC-3' and 23S-R 5'-CMACCAAGATCTGCACTAG-3' was used. The PCR components included 25 µl solution (PCR Master Mix, Promega, Madison, WI, USA), and 1 µl (400 ng) of the total DNA obtained in the extraction. Subsequently, the 810 bp COI gene was also amplified for molecular characterization (CO1-F 5'-GGTTCAGGTGTTGGTTGGAC-3' and CO1-R 5'-AATCCAATAACCGCACCAAG-3'). The positive control was obtained from samples previously confirmed by sequencing (Oliveira et al. 2018 ) and as a negative control, oligonucleotides were used together with the PCR Master Mix and nuclease-free ultrapure water. The cycling parameters for amplification were obtained from previous studies (Oliveira et al. 2018 ). A positive result (amplification) was obtained by PCR for 23S rRNA gene and for the COI gene. To confirm the genes, the amplified DNA products (amplicons) were sequenced. For this step, the amplicons were purified using the kit (PureLink® PCR Purification Kit), according to the mannufacter’s recommendations. The amplified products were sequenced in the forward and reverse directions, using the Sanger method, by capillary electrophoresis in an automated sequencer (ABI 310, Applied Biosystems) using the kit (ABI Taq DyeDeoxy Terminator version 3.1 Cycle Sequencing Kit) according to the producer's instructions (Applied Biosystems, Inc., Foster City, California, USA). The sequences obtained were subjected to basic local alignment search tool (BLAST) analysis. For 23S ribosomal RNA gene, BLAST search showed 95,15% of the genetic identity with the large 23S ribosomal RNA gene of Atoxoplasma spp. with 100% coverage and an E value of 9e-144. Using Geneious prime software (version 2014 0.5), the sequences obtained were analyzed and consensus sequences were obtained for the COI gene. Subsequently, the evolutionary history for the COI gene was conducted in MEGA11 and inferred by using the Maximum Likelihood method and Tamura-Nei model. The amplified sequences of the COI showed 99.5% genetic identity with Isospora sp. (OL999212) from the purple honeycreeper ( Cyanerpes caeruleus ) from San Diego Zoo (USA) with a recent common ancestor, and 97.50% genetic identity to Isospora sp. (PQ595904) from the Brazilian wild black-goggled tanagers ( Trichothaupis melanpps ), but with a more distant common ancestor. Both had 100% coverage and an E value of 0.00. Isospora species of passerine from China, Europe and Australia are also shown in the phylogenetic tree (Fig. 3 ). Discussion Although systemic isosporosis has been reported in many species of passerines, reports are not frequent in Brazil and the disease has never been documented in great-billed seed finch. The great-billed seed finch ( Sporophila maximiliani ) is considered endangered due to the rapid reduction of its native population in general, with large areas of complete extirpation in southeastern Brazil (BirdLife International 2023 ). This passerine resists pressures from intensive capture, since it is highly valued as a pet, suffering from illegal trade and also from the degradation of its habitat (Destro et al. 2012 ; Machado et al. 2019 ). Currently, in Brazil, there are ex-situ conservation programs for great-billed seed finch, such as programs that establish protected areas for raising these birds in captivity, foreseeing their reintroduction into the wild (Machado et al. 2019 ). This report documents ten cases of fatal systemic isosporosis in these captive birds, and should therefore be considered an important disease in ex situ conservation programs for this species. Furthermore, although most parasite lineages are probably host-specific, interspecies transmission may occur (Schrenzel et al. 2005 ). Consequently, restriction of species mixing deserves consideration in the management of passerines, especially those threatened with extinction. In nature, these parasites are endemic at low tissue levels (van Riper et al. 1987 ; Flech et al. 2022), although tissue levels are likely underestimated due to the difficulty in identifying circulating merozoites (Middleton et al. 1983). In captivity, systemic isosporosis has become a significant cause of mortality, particularly in zoos and research facilities housing colonies of passerine birds captured in the wild (Rossi et al. 1997 ). The stress of captivity and poor sanitary conditions have been identified as contributing factors to the high morbidity in such facilities (McNamee et al. 1995 ; Flech et al. 2022). Additionally, these factors, along with the animal's age, may be associated with the development of the parasite's extraintestinal stage, leading to a systemic and fatal disease (Schrenzel et al. 2005 ). In the present report, all evaluated animals were from captivity. Systemic isosporosis can affect both young and adult birds (Adkesson et al. 2005 ). Studies suggest that the extraintestinal stages of these coccidia are highly pathogenic for young birds, with mortality rates reaching up to 80% (Adkesson et al. 2005 ; Jamriška et al. 2013 ). In the present case, there was no significant difference in the number of cases between juveniles and adults, as 53% of the birds were juveniles and 47% were adults. However, canaries 2, 3, and 4 originated from the same farm, where juvenile mortality reached 80% (4/5). Additionally, the beginning of mortality coincided with the introduction of an adult bird of the same species to the facility. Studies indicate that adult birds may not exhibit clinical signs while shedding a large number of infectious oocysts into the environment (Maslin and Latimer 2009 ). Although fecal oocyst testing was not performed on the introduced adult bird, it is possible that this individual served as the source of infection for the juveniles. Depending on the host species and the stage of infection, the occurrence of histological lesions can vary significantly among organs. In the intestine, lesions may present with different patterns and localizations. Some animals exhibit enteritis with inflammatory infiltrates confined to the lamina propria, associated with necrosis and hemorrhage (Oliveira et al. 2018 ; Terio and Adkesson 2019 ). Others display transmural enteritis with intense lymphocytic infiltrates, resembling lymphoma (Cushing et al. 2011 ). In the present study, 8/10 great-billed seed finches exhibited transmural intestinal lesions predominantly in the duodenum and jejunum. These lesions were characterized by numerous lymphocytes and macrophages replacing crypts and villi, while lesions in other organs were scarce. As this is the first documented report of systemic isosporosis in great-billed seed finches, it is possible that this represents the most common presentation of the disease in this species. In green-winged saltators, systemic isosporosis typically affects the spleen, liver, and small intestine; however, lesions in the kidneys, heart, and lungs may also occur (Oliveira et al. 2018 ). In the present study, findings in the green-winged saltator (case 5) were consistent with changes in multiple organs, with a predominance in the small intestine, liver, spleen, and heart. To better characterize the pathogen in one of the birds (green-winged saltator), the mitochondrial cytochrome c oxidase subunit 1 (COI) gene was amplified and sequenced. This gene has been shown to be reliable for detecting a diverse range of Isospora spp. sequences (Kubiski et al. 2022 ). In this study, the sequenced sample exhibited over 99% identity with sequences of Isospora spp. isolates from a purple honeycreeper ( Cyanerpes caeruleus ) at the San Diego Zoo (Kubiski et al. 2022 ). This bird belongs to the family Thraupidae, the same family as the green-winged saltators, and it is native to Brazil, specifically to the western Amazon. Similar to other genera in the family Eimeriidae, parasites of the genus Isospora spp. are known to exhibit host specificity (Schrenzel et al. 2005 ). However, interspecific transmission is possible in mixed-species environments (Kubiski et al. 2022 ). Furthermore, experimental studies suggest that parasite species with life cycles restricted to the gastrointestinal tract are host-specific, whereas those with asexual stages that multiply in mononuclear cells as part of their life cycle exhibit unknown specificity (Box 1970). These findings may explain the genetic identity between the parasite in the present case and that of a different avian species. The genetic identity of 97.50% with Isospora sp. from Brazil does not indicate that it is the same parasite species. Although the similarity threshold for the COI gene is not well defined, the 1% divergence in other genetic targets may suggest a different species of Isospora . Based on the phylogenetic tree, a clear ancestral distance was observed between the our sample from green-winged saltator, and the other Brazilian isolate, indicating that they are probably distinct species. Conclusion The combination of gross and microscopic findings enabled the diagnosis of systemic isosporiasis in the birds of the present study. PCR and sequencing confirmed Isospora sp. in green-winged saltator. This report is the first description of systemic isosporiasis in great-billed seed finches, characterized by severe enteritis that primarily affects the small intestine. The intestine and liver were the organs most frequently affected. The impact of this disease on wild populations of great-billed seed finches is still unknown; however, this report highlights the significance of the disease in captive populations. Histological changes in canaries and green-winged saltators are similar to those reported previously, with young canaries being possibly more susceptible. Declarations Declaration of competing interests The authors declared no conflicts of interest in relation to the research, authorship or publication of this article. Author Contributions Camila Issa Amaral: Investigation, Data Curation, Methodology, Writing - Original Draft. Ayisa Rodrigues de Oliveira: Methodology, Writing - Review & Editing Eric Santos Oliveira: Writing - Review & Editing Marcelo Coelho Lopes: Methodology, Writing - Review & Editing Maira dos Santos Carneiro Lacerda : Investigation, Writing - Review & Editing Marcelo Pires Nogueira de Carvalho: Methodology, Writing - Review & Editing Roselene Ecco: Investigation, Supervision, Writing - Review & Editing. Acknowledgments R. Ecco was supported by a fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico (National Council for Scientific and Technological Development), C. I. Amaral, E.S. Oliveira, M. C. Lopes, M. S. C. Lacerda were supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Coordination of Improvement of Higher Education Personnel), Brazil, Finance Code 001. Ethical statement The authors confirm that the animals were treated with the veterinary standard of care according to specific requirements of our institution for ethics approval. References Adkesson MJ, Zdziarski JM, Little SE (2005). Atoxoplasmosis in tanagers. J Zoo Wildl Med 36:265–272 https://doi.org/10.1638/03-091.1 Ball SJ, Brown MA, Daszak P, Pittilo RM (1998). Atoxoplasma (Apicomplexa: Eimeriorina: Atoxoplasmatidae) in the greenfinch (Carduelis chloris). J Parasitol 84(4):813-7. BirdLife International. Species factsheet: Sporophila maximiliani. Downloaded from http://datazone.birdlife.org/species/factsheet/great-billed-seed-finch-sporophila-maximiliani on 2023 Nov 16. Brasil (2016) Sumário executivo—Livro Vermelho da Fauna Brasileira Ameaçada de Extinção. Cooper JE, Gschmeissner S, Greenwood AG (1989). Atoxoplasma in greenfinches ( Carduelis chloris ) as a possible cause of ‘‘going light.’’ Vet Rec 124(5):343–344. https://doi.org/10.1136/vr.124.13.343 Cushing TL, Schat KA, States SL, Grodio JL, O'Connell PH, Buckles EL (2011). Characterization of the host response in systemic Isosporosis (Atoxoplasmosis) in a Colony of captive American goldfinches ( Spinus tristis ) and house sparrows ( Passer domesticus ). Vet Path 985:985–992. https://doi.org/10.1177/0300985810391114 Destro GFG, Pimentel TL, Monti R, Sabaini RM, Borges RC, Barreto R (2012). Efforts to combat wild animals trafficking in Brazil. In: Lameed GA (ed) Biodiversity enrichment in a diverse world. Intech Open, London pp 33–36. Flach EJ, Dodhia HS, Guthrie A, Blake DP (2022). Systemic isosporiasis (atoxoplasmosis) in passerine birds at the Zoological Society of London, London Zoo. J Zoo Wildl Med 53(1):70-82. https://doi.org/10.1638/2021-0087 Gill H, Paperna I (2008). Proliferative visceral Isospora (atoxoplasmosis) with morbid impact on the Israeli sparrow ( Passer domesticus biblicus Hartert, 1904). Parasitol Res 103(3):493–499 https://doi.org/10.1007/s00436-008-0986-4 Jamriška J, Lavilla LA, Thomasson A, Barbon AR, Lopéz JF, Modrý D (2013). Treatment of atoxoplasmosis in the Blue-crowned Laughing Thrush ( Dryonastes courtoisi ). Avian Pathol 42(6):569-571 https://doi.org/10.1080/03079457.2013.854309 Khan RA, Desser SS (1971). Avian Lankesterella infections in Algonquin Park, Ontario. Can J Zool 49(8):1105–1110. DOI: https://doi.org/10.1139/z71-171 Levine ND (1982). The genus Atoxoplasma (Protozoa, Apicomplexa). J Parasitol 68(4):719-723 https://doi.org/10.2307/3280933 Lindstrom KM, Dolnik O, Yabsley M, Hellgren O, O’Connor B, Parn H, Foufopoulos J (2009). Feather mites and internal parasites in small ground finches (Geospiza fuliginosa, Emberizidae) from the Galapagos Islands (Ecuador). J Parasitol 95(1):39–45 https://doi.org/10.1645/GE-1655.1 Luna LG (1968). Manual of histologic staining methods of the Armed Forces Institute of Pathology, 3rd Edn. McGraw-Hill, New York. Machado RB, Silveira LF, Gomes da Silva MIS, Ubaid FK, Medolago CA, Francisco MR, Dianese JC (2019). Reintroduction of songbirds from captivity: the case of the Great billed Seed finch ( Sporophila maximiliani ) in Brazil. Biodivers Conserv 29:1613–1636 https://doi.org/10.1007/s10531-019-01830-8 Maslin WR, Latimer KS (2009). Atoxoplasmosis in canary fledglings: severe lymphocytic enteritis with preferential parasitism of B lymphocytes. Avian Dis 3:473-476 https://doi.org/10.1637/8557-121008-Case.1 McNamee P, Pennycott T, McConnel S (1995). Clinical and pathological changes associated with atoxoplasma in a captive bullfinch ( Pyrrhula pyrrhula ). Vet Rec 136(3):221–222 https://doi.org/10.1136/vr.136.9.221 Middleton AL, Julian RJ (1983). Lymphoproliferative disease in the American goldfinch, Carduelis tristis. J Wildl Dis 19(3):280-285 https://doi.org/10.7589/0090-3558-19.3.280 Mohr F, Betson M, Quintard B. Investigation of the presence of Atoxoplasma spp (2017). in Blue-crowned Laughingthrush ( Dryonastes courtoisi ) adults and neonates. J Zoo Wildl Med 48(1):1–6 https://doi.org/10.1638/2016-0044.1 Mugridge NB, Morrison DA, Jäkel T, Heckeroth AR, Tenter AM, Johnson AM (2000). Effects of sequence alignment and structural domains of ribosomal DNA on phylogeny reconstruction for the protozoan family Sarcocystidae. Mol Biol Evol 17(12):1842-1853 https://doi.org/10.1093/oxfordjournals.molbev.a026285 Oliveira AR, Souza TD, Mol JPS, Flecher MC, Hiura E, Santos RL. Pathological and molecular characterization of systemic isosporosis (atoxoplasmosis) in captive green-winged saltator ( Saltator similis ) (2018). Vet Parasitol May 15;255:98-101 https://doi.org/10.1016/j.vetpar.2018.04.007 Partington CJ, Gardiner CH, Fritz D, Phillips LG, Montail RJ (1989). Atoxoplasmosis in Bali mynahs ( Leucospar rothschildi ). J Zoo Wildl Med 20(3):328–335 https://doi.org/10.2307/41262613 Pennycott TW, Ross HM, McLaren IM, Park A, Hopkins GF, Foster G (1998). Causes of death of wild birds of the family Fringillidae in Britain. Vet Rec 143(3):155–158 https://doi.org/10.1136/vr.143.6.155 Quiroga MI, Aleman N, Vazquez S, Nieto JM (2000). Diagnosis of atoxoplasmosis in a canary ( Serinus canarius ) by histopathologic and ultrastructural examination. Avian Dis 44:465–469. Rossi G, Perrucci S, Taccini E, Vitali CG, Braca G, Renzoni G (1997). Mortality in black siskins ( Carduelis atrata ) with systemic coccidiosis. J Wildl Dis 33(1):152-157 https://doi.org/10.7589/0090-3558-33.1.152 Sánchez-Cordón PJ, Go´mez-Villamandos JC, Gutie´rrez J, Sierra MA, Pedrera M, Bautista MJ (2007). Atoxoplasma spp. infection in captive canaries ( Serinus canaria ). J Vet Med A Physiol Pathol Clin Med 54(1):23–26. https://doi.org/10.1111/j.1439-0442.2007.00909.x Schrenzel MD, Maalouf GA, Gaffney PM, Tokarz D, Keener LL, McClure D, Griffey S, McAloose D, Rideout BA (2005). Molecular characterization of isosporoid coccidia ( Isospora and Atoxoplasma spp.) in passerine birds. J Parasitol 91(3):635-647 https://doi.org/10.1645/GE-3310 Terio KA, Adkesson MJ (2019). Systemic isosporosis in passerine birds. In: Miller ER, Lamberski N, Calle P (eds.). Fowler’s Zoo and Wild Animal Medicine, Elsevier, St. Louis (MO), pp 454–458. Box ED (1975) Exogenous stages of Isospora serini (Aragão) and Isospora canaria sp. n. in the canary ( Serinus canarius Linnaeus). J Protozool 22(2):165-169 https://doi.org/10.1111/j.1550-7408.1975.tb05844.x van Riper C 3rd, van Riper S, Laird M (1987) Discovery of Atoxoplasma in Hawaii. J Parasitol 73(5):1071-1073. Kubiski SV, Witte C, Burchell JA, Conradson D, Zmuda A, Barbon AR, Vilches-Moure JG, Felt SA, Rideout BA (2022). Mitochondrial Gene Diversity and Host Specificity of Isospora in Passerine Birds. Front Vet Sci 29;9:847030. https://doi.org/10.1111/10.3389/fvets.2022.847030 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Jun, 2025 Read the published version in Veterinary Research Communications → Version 1 posted Editorial decision: Revision requested 21 Apr, 2025 Reviews received at journal 21 Apr, 2025 Reviews received at journal 16 Apr, 2025 Reviews received at journal 15 Apr, 2025 Reviewers agreed at journal 07 Apr, 2025 Reviews received at journal 06 Apr, 2025 Reviewers agreed at journal 06 Apr, 2025 Reviewers agreed at journal 06 Apr, 2025 Reviewers agreed at journal 05 Apr, 2025 Reviewers agreed at journal 05 Apr, 2025 Reviewers invited by journal 04 Apr, 2025 Editor assigned by journal 03 Apr, 2025 Submission checks completed at journal 03 Apr, 2025 First submitted to journal 31 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6346858","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":445853369,"identity":"35d4422c-99c6-4092-beb5-8ab2ea4c1d14","order_by":0,"name":"Camila Issa Amaral","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Camila","middleName":"Issa","lastName":"Amaral","suffix":""},{"id":445853370,"identity":"9ddbf2ac-daa8-45d4-a47b-ce5dda531f65","order_by":1,"name":"Ayisa Rodrigues de Oliveira","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Ayisa","middleName":"Rodrigues","lastName":"de Oliveira","suffix":""},{"id":445853371,"identity":"330b5dc1-66d7-4d03-88c5-e0ca90b4e9bb","order_by":2,"name":"Eric Santos Oliveira","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Eric","middleName":"Santos","lastName":"Oliveira","suffix":""},{"id":445853372,"identity":"7b5e24ba-725d-418c-b38e-2fe6a2a11de0","order_by":3,"name":"Marcelo Coelho Lopes","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Marcelo","middleName":"Coelho","lastName":"Lopes","suffix":""},{"id":445853373,"identity":"25324024-63b6-42a9-afa7-238a89b4760a","order_by":4,"name":"Maira dos Santos Carneiro Lacerda","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Maira","middleName":"dos Santos Carneiro","lastName":"Lacerda","suffix":""},{"id":445853374,"identity":"8052bbdd-41be-461d-bcec-30b3c5287c9f","order_by":5,"name":"Marcelo Pires Nogueira Carvalho","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":false,"prefix":"","firstName":"Marcelo","middleName":"Pires Nogueira","lastName":"Carvalho","suffix":""},{"id":445853375,"identity":"e386e018-bdcb-4546-841d-4fd36ccb9dff","order_by":6,"name":"Roselene Ecco","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvUlEQVRIiWNgGAWjYLCCD2CS8QGQOECcDsYZDAwSDAzMBsRrYeYhSQs/++GHj23bbOoYJJJZN35huJNPUItkT5qxcW5bmgRQC9ttGYZnlg2EtBjc4GGTzjlzGKgl/9htCYbDBgRtsQdpsTjzH2ILUVoMJIBaGCoOgLXc/ECMFokzacaGPRXJkm08j9luMxg8I6yFv/3wwwc/DOz4+dmBtvyouENYCxywMYAiiAQNEMD4g1Qdo2AUjIJRMCIAAN+TNIEzktapAAAAAElFTkSuQmCC","orcid":"","institution":"Universidade Federal de Minas Gerais - UFMG","correspondingAuthor":true,"prefix":"","firstName":"Roselene","middleName":"","lastName":"Ecco","suffix":""}],"badges":[],"createdAt":"2025-03-31 17:08:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6346858/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6346858/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11259-025-10785-x","type":"published","date":"2025-06-13T15:56:57+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":81937468,"identity":"5aaeb91a-910b-4066-ac7c-5b7bcd0f221d","added_by":"auto","created_at":"2025-05-05 06:28:13","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":25333,"visible":true,"origin":"","legend":"\u003cp\u003eDistribution graph of systemic isosporosis (atoxoplasmosis) histologic lesions according to the species affected. \u003cem\u003eSporophila maximiliani\u003c/em\u003e (n=10), \u003cem\u003eSerinus canaria\u003c/em\u003e (n=4) and \u003cem\u003eSaltator similis\u003c/em\u003e (n=1).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6346858/v1/82b6cf450f891409a03bf2e7.jpg"},{"id":81937469,"identity":"2e66d2e7-0373-4342-803b-d219cd7d7ce6","added_by":"auto","created_at":"2025-05-05 06:28:13","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":241279,"visible":true,"origin":"","legend":"\u003cp\u003ePathological findings of systemic isosporosis in different passerine species. \u003cstrong\u003eA-C\u003c/strong\u003e \u003cstrong\u003eImages of great-billed seed finches.\u003c/strong\u003e (A) Cross-sections of the small intestine. Intestinal wall markedly thickened, diffusely white, with lumen stenosis. (B) Subgross image of the small intestine. Diffusely thickened intestinal wall with pronounced lumen stenosis (H\u0026amp;E). (C) Histological image of the small intestine. A focal extensive area with transmural inflammatory infiltrate (arrow) (H\u0026amp;E 4x). \u003cstrong\u003eD-F Images of the green-winged saltator.\u003c/strong\u003e (D) Gross image of the small intestine. Serosal and mucosal hyperemia with a moderate amount of friable, yellowish material in the lumen. (E) Histological image of the small intestine. Necrosis with intense fibrin deposition and inflammatory infiltrate in the deep layer of the mucosa (arrow) (H\u0026amp;E 20x). (F) Microscopic image of the small intestine. \u003cem\u003eIsospora\u003c/em\u003e spp. merozoites, 2-3 µm in size, rounded, basophilic, located intracellularly within macrophages and lymphocytes and extracellularly (arrow) (H\u0026amp;E 100x). \u003cstrong\u003eG-K Images of canaries\u003c/strong\u003e. (G) Gross image of the liver. Multifocal to coalescing yellow and friable areas (necrosis). (H) Histological image of the liver. Hepatic parenchyma diffusely disorganized, with extensive multifocal necrotic areas (arrow) interspersed with intense inflammatory infiltrate (arrowhead) (H\u0026amp;E 20x). (I) Microscopic image of the liver. \u003cem\u003eIsospora\u003c/em\u003e spp. merozoites within histiocytes, 2-3 µm in size, rounded, basophilic, surrounded by a clear halo (arrow) (H\u0026amp;E 100x). (J) Microscopic image of the heart. Pericardium markedly thickened due to inflammatory infiltrate, which extends slightly into the myocardium (H\u0026amp;E 10x). (K) Microscopic image of the lung. Parabronchus with moderately thickened air capillary septa due to inflammatory infiltrate (H\u0026amp;E 20x)\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6346858/v1/1ea4ac05f46160502e20c75b.jpg"},{"id":81939637,"identity":"3137027b-3df4-4a93-8cc3-ea107cd1f3c7","added_by":"auto","created_at":"2025-05-05 06:44:13","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":62930,"visible":true,"origin":"","legend":"\u003cp\u003ePhylogenetic tree of \u003cem\u003eIsospora\u003c/em\u003e spp. (Sample ID 5) and related taxa was created using MEGA 11 based on our alignment. The tree with the highest log likelihood (-1772.50) is shown. Initial tree for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the Tamura-Nei model, and then selecting the topology with superior log likelihood value. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. The proportion of sites where at least 1 unambiguous base is present in at least 1 sequence for each descendent clade is shown next to each internal node in the tree. This analysis involved 19 nucleotide sequences.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6346858/v1/b2c58c160e672fa24e5eaaed.jpg"},{"id":84726439,"identity":"a03b16b4-9902-4ee1-a52f-8cbdf9bb58f3","added_by":"auto","created_at":"2025-06-16 16:03:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1068576,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6346858/v1/de8d828c-f586-4379-9a78-4c611a4240fe.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Systemic isosporosis in different species of passerine birds","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSystemic isosporosis, previously referred as atoxoplasmosis, is an infectious disease caused by apicomplexan protozoa of the genus \u003cem\u003eIsospora\u003c/em\u003e. These parasites can induce diseases confined to the gastrointestinal system or lead to systemic alterations, causing lesions in multiple organs (Ball 1998; Adkesson et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Flach et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This disease has been reported in a wide range of passerine species, including house sparrows (\u003cem\u003ePasser domesticus\u003c/em\u003e) (Gill et al. 2008), canaries (\u003cem\u003eSerinus canaria\u003c/em\u003e) (Quiroga et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Maslin and Latimer \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; S\u0026aacute;nchez-Cord\u0026oacute;n et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2007\u003c/span\u003e), european greenfinches (\u003cem\u003eCarduelis chloris\u003c/em\u003e) (Cooper et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1989\u003c/span\u003e), rose-breasted grosbeaks (\u003cem\u003ePheucticus ludovicianus\u003c/em\u003e) (Khan et al. 1971), Bali mynahs (\u003cem\u003eLeucopsar rothschildi\u003c/em\u003e) (Partington et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1989\u003c/span\u003e), various finch species (Pennycott et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Lindstrom et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), different tanager species (Adkesson et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), blue-crowned laughingthrush (\u003cem\u003eDryonastes courtoisi\u003c/em\u003e) (Mohr et al. 2017), green-winged saltators (\u003cem\u003eSaltator similis\u003c/em\u003e) (Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), goldfinches (Gosbel et al. 2020), and others.\u003c/p\u003e \u003cp\u003eThe life cycle of these coccidia has been the subject of experimental and descriptive studies, but remains poorly understood. In summary, the parasite is transmitted via fecal-oral route (Levine \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1982\u003c/span\u003e), and asexual reproduction (merogony) in both enterocytes and macrophages or lymphocytes leads to the dissemination of merozoites to other organs (Adkesson et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Sexual reproduction (gametogony) occurs in enterocytes, primarily in the duodenum, of the same host. Histopathological analysis showed that various organs, such as the intestine, liver, and spleen, can exhibit inflammatory infiltrates composed of lymphocytes, plasma cells, and macrophages, along with variable amounts of intracellular merozoite aggregates (Maslin and Latimer \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; S\u0026aacute;nchez-Cord\u0026oacute;n et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe systemic form of isosporosis is a significant cause of mortality in passerines, particularly in young birds and those kept in captivity. Factors such as high population densities and mixed-species aviaries result in increased shedding of infectious oocysts, potentially exacerbating the clinical condition (Rossi et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1997\u003c/span\u003e). This is particularly concerning for rare and endangered species, as well as for birds bred for release into the wild, which may expose threatened free-ranging populations to a novel pathogen (Kubiski et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis study aimed to report systemic isosporosis causing fatal disease in three different passerine species: great-billed seed finch (\u003cem\u003eSporophila maximiliani\u003c/em\u003e), island canary (\u003cem\u003eSerinus canaria\u003c/em\u003e), and green-winged saltator (\u003cem\u003eSaltator similis\u003c/em\u003e). Although this disease has been previously documented in a wide range of passerine species, this is the first documented report of systemic isosporosis in great-billed seed finch. While all three reported species face threats from habitat degradation and illegal bird trade in Brazil, only the great-billed seed finch is currently classified as globally endangered by the International Union for Conservation of Nature (IUCN) (BirdLife International, 2017) and critically endangered according to Brazilian authorities (Brasil, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). This study also aimed to describe the anatomopathological and molecular findings of the disease in passerine species from different locations in Minas Gerais, Brazil. The research highlights the significance of this disease in captive birds and those threatened with extinction.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eCollection history\u003c/h2\u003e \u003cp\u003eBetween 2017 and 2022, 15 passerines were diagnosed with systemic isosporosis through post-mortem examination and histopathology at the Veterinary School ofUniversidade Federal de Minas Gerais. The birds belonged to the following species: great-billed seed finch (\u003cem\u003eSporophila maximiliani\u003c/em\u003e) (10/15), island canary (\u003cem\u003eSerinus canaria\u003c/em\u003e) (4/15), and green-winged saltator (\u003cem\u003eSaltator similis\u003c/em\u003e) (1/15). All birds died naturally and originated from different breeding facilities located in Minas Gerais, Brazil (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCases of systemic isosporosis received at the Veterinary School of UFMG from 2017 to 2022.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample ID\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eReceived year\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSpecies (commom name)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFamily\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFarm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSerinus canaria\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(island canary)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFringillidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSerinus canaria\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(island canary)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFringillidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSerinus canaria\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(island canary)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFringillidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSaltator similis\u003c/em\u003e (green-winged saltator)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFringillidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e(\u003c/em\u003egreat-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e(\u003c/em\u003egreat-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSerinus canaria\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(island canary)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFringillidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e(\u003c/em\u003egreat-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJuvenile\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eSporophila maximiliani\u003c/em\u003e\u003c/p\u003e \u003cp\u003e(great-billed seed finch)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThraupidae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdult\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eClinical presentations\u003c/h3\u003e\n\u003cp\u003eClinical signs were similar across all birds and included inappetence, ruffled plumage, hyporexia, reduced activity, diarrhea, and death. The disease progression ranged from two to ten days, with mortality rates varying between breeding sites from 5\u0026ndash;33.3%. All birds were housed in individual cages and fed a diet of mixed seeds and fruits.\u003c/p\u003e \u003cp\u003eThe canaries in 2, 3 and 4 originated from a farm composed of 15 birds of the same species, with ten adults and five chicks. Four chicks died, and the onset of mortality coincided with the introduction of a new adult bird of the same species to the aviary.\u003c/p\u003e \u003cp\u003eFor the great-billed seed finches 9\u0026ndash;13, only formalin fixed samples of organs (intestine, liver, lungs, heart, and proventriculus) for histopathological examination were received, and no clinical history or epidemiological data were provided.\u003c/p\u003e\n\u003ch3\u003eAnatomopathological examination\u003c/h3\u003e\n\u003cp\u003eTwelve out of 15 birds were grossly examined, and ten (10/12) presented poor body condition, evidenced by a prominent keel and marked atrophy of pectoral muscles, while two birds displayed good body condition. During necropsy, samples of liver, spleen, pancreas, proventriculus, gizzard, small intestine, large intestine, kidneys, lungs, pectoral muscle, heart and brain were collected, fixed in 10% buffered formalin, subjected to routine processing, embedded in paraffin, sectioned at 4 \u0026micro;m and stained with hematoxylin and eosin (H\u0026amp;E) (Luna, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1968\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAll birds were diagnosed with systemic isosporosis by histopathological examination, with some variations in the affected species and organs. The main lesions associated with the parasite included enteritis, hepatitis, pneumonia, myocarditis, splenitis, and myositis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn great-billed seed finch, the most consistent gross lesions were observed in the duodenum and jejunum, characterized by markedly thickened walls with luminal stenosis (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). Microscopically, all true finches (10/10) exhibited transmural disorganization of the duodenal and jejunal architecture, with loss of villous structure and replacement of intestinal crypts by intense inflammatory infiltrate (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb), predominantly composed of lymphocytes, with fewer macrophages. In eight birds (8/10), the inflammatory infiltrate occasionally extended beyond the intestinal wall, reaching the serosal surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec). In all examined sections, merozoites of \u003cem\u003eIsospora\u003c/em\u003e sp. measured 2\u0026ndash;3 \u0026micro;m, were round, basophilic, and surrounded by a clear halo. The merozoites were observed within macrophages, lymphocytes, enterocytes, and extracellularly. In four birds (4/10), moderate to marked multifocal to coalescent lymphohistiocytic hepatitis with intralesional merozoites was also noted.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the green-winged saltator, all intestinal segments were distended, with diffuse hyperemia of the serosa with moderate thickening of the duodenal and jejunal walls. On the surface of mucosa there was moderate amount of friable and yellowish material (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed). Histologically, the mucosa and submucosa of the small intestine exhibited circumferential necrosis and marked fibrin deposition, associated with a moderate inflammatory infiltrate composed of lymphocytes and macrophages (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee). Merozoites compatible with \u003cem\u003eIsospora\u003c/em\u003e sp. were observed within macrophages and extracellularly (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef). Additionally, lymphocytic and histiocytic hepatitis, myocarditis, splenitis, and myositis were noted, all associated with merozoites compatible with \u003cem\u003eIsospora\u003c/em\u003e spp. located inside machophages and lymphocytes, as well as extracellularly.\u003c/p\u003e \u003cp\u003eIn the canaries, all intestinal segments were distended with diffuse serosal hyperemia, and the lumen was filled with hemorrhagic content. In the liver of one bird (1/4), there were multifocal to coalescing white-yellow friable areas that extended into the parenchyma (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eg). The lungs of three canaries (3/4) were non-collapsed, slightly consolidated, and diffusely red. Microscopically, the liver had extensive multifocal areas of necrosis, and marked inflammatory infiltrate (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eh) composed of lymphocytes and macrophages associated with \u003cem\u003eIsospora\u003c/em\u003e sp. merozoites (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ei). Two canaries (2/4) presented lymphocytic and histiocytic pericarditis and myocarditis (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ej). with few extracellular \u003cem\u003eIsospora\u003c/em\u003e spp. merozoites In the lungs of three birds (3/4), there was marked diffuse interstitial lymphocytic and histiocytic pneumonia (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ek) associated with some intra-histiocytic and extracellular \u003cem\u003eIsospora\u003c/em\u003e spp. merozoites.\u003c/p\u003e\n\u003ch3\u003ePolimerase chain reaction (PCR) and sequencing\u003c/h3\u003e\n\u003cp\u003eDNA was extracted from frozen tissue samples (liver, spleen, and intestine) from one case (\u003cem\u003eSaltator similis\u003c/em\u003e, case 5) using the Qiagen DNeasy Kit (Valencia, California, USA) as recommended by the manufacturer. Polymerase chain reaction (PCR) was used to amplify a 1,495 bp portion (Mugridge et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Schrenzel et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) of the large chromosomal ribosomal RNA subunit of the 23S gene (23S rRNA). For reaction, 0.2 \u0026micro;M of each oligonucleotide named 23S-F 5'-TACCCGCTGAACTTAAGC-3' and 23S-R 5'-CMACCAAGATCTGCACTAG-3' was used. The PCR components included 25 \u0026micro;l solution (PCR Master Mix, Promega, Madison, WI, USA), and 1 \u0026micro;l (400 ng) of the total DNA obtained in the extraction. Subsequently, the 810 bp COI gene was also amplified for molecular characterization (CO1-F 5'-GGTTCAGGTGTTGGTTGGAC-3' and CO1-R 5'-AATCCAATAACCGCACCAAG-3'). The positive control was obtained from samples previously confirmed by sequencing (Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) and as a negative control, oligonucleotides were used together with the PCR Master Mix and nuclease-free ultrapure water. The cycling parameters for amplification were obtained from previous studies (Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA positive result (amplification) was obtained by PCR for 23S rRNA gene and for the COI gene. To confirm the genes, the amplified DNA products (amplicons) were sequenced. For this step, the amplicons were purified using the kit (PureLink\u0026reg; PCR Purification Kit), according to the mannufacter\u0026rsquo;s recommendations. The amplified products were sequenced in the forward and reverse directions, using the Sanger method, by capillary electrophoresis in an automated sequencer (ABI 310, Applied Biosystems) using the kit (ABI Taq DyeDeoxy Terminator version 3.1 Cycle Sequencing Kit) according to the producer's instructions (Applied Biosystems, Inc., Foster City, California, USA).\u003c/p\u003e \u003cp\u003eThe sequences obtained were subjected to basic local alignment search tool (BLAST) analysis. For 23S ribosomal RNA gene, BLAST search showed 95,15% of the genetic identity with the large 23S ribosomal RNA gene of \u003cem\u003eAtoxoplasma\u003c/em\u003e spp. with 100% coverage and an E value of 9e-144. Using Geneious prime software (version 2014 0.5), the sequences obtained were analyzed and consensus sequences were obtained for the COI gene. Subsequently, the evolutionary history for the COI gene was conducted in MEGA11 and inferred by using the Maximum Likelihood method and Tamura-Nei model. The amplified sequences of the COI showed 99.5% genetic identity with \u003cem\u003eIsospora\u003c/em\u003e sp. (OL999212) from the purple honeycreeper (\u003cem\u003eCyanerpes caeruleus\u003c/em\u003e) from San Diego Zoo (USA) with a recent common ancestor, and 97.50% genetic identity to \u003cem\u003eIsospora\u003c/em\u003e sp. (PQ595904) from the Brazilian wild black-goggled tanagers (\u003cem\u003eTrichothaupis melanpps\u003c/em\u003e), but with a more distant common ancestor. Both had 100% coverage and an E value of 0.00. \u003cem\u003eIsospora\u003c/em\u003e species of passerine from China, Europe and Australia are also shown in the phylogenetic tree (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAlthough systemic isosporosis has been reported in many species of passerines, reports are not frequent in Brazil and the disease has never been documented in great-billed seed finch. The great-billed seed finch (\u003cem\u003eSporophila maximiliani\u003c/em\u003e) is considered endangered due to the rapid reduction of its native population in general, with large areas of complete extirpation in southeastern Brazil (BirdLife International \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). This passerine resists pressures from intensive capture, since it is highly valued as a pet, suffering from illegal trade and also from the degradation of its habitat (Destro et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Machado et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Currently, in Brazil, there are \u003cem\u003eex-situ\u003c/em\u003e conservation programs for great-billed seed finch, such as programs that establish protected areas for raising these birds in captivity, foreseeing their reintroduction into the wild (Machado et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). This report documents ten cases of fatal systemic isosporosis in these captive birds, and should therefore be considered an important disease in \u003cem\u003eex situ\u003c/em\u003e conservation programs for this species. Furthermore, although most parasite lineages are probably host-specific, interspecies transmission may occur (Schrenzel et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Consequently, restriction of species mixing deserves consideration in the management of passerines, especially those threatened with extinction.\u003c/p\u003e \u003cp\u003eIn nature, these parasites are endemic at low tissue levels (van Riper et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1987\u003c/span\u003e; Flech et al. 2022), although tissue levels are likely underestimated due to the difficulty in identifying circulating merozoites (Middleton et al. 1983). In captivity, systemic isosporosis has become a significant cause of mortality, particularly in zoos and research facilities housing colonies of passerine birds captured in the wild (Rossi et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1997\u003c/span\u003e). The stress of captivity and poor sanitary conditions have been identified as contributing factors to the high morbidity in such facilities (McNamee et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Flech et al. 2022). Additionally, these factors, along with the animal's age, may be associated with the development of the parasite's extraintestinal stage, leading to a systemic and fatal disease (Schrenzel et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). In the present report, all evaluated animals were from captivity.\u003c/p\u003e \u003cp\u003eSystemic isosporosis can affect both young and adult birds (Adkesson et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Studies suggest that the extraintestinal stages of these coccidia are highly pathogenic for young birds, with mortality rates reaching up to 80% (Adkesson et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Jamriška et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). In the present case, there was no significant difference in the number of cases between juveniles and adults, as 53% of the birds were juveniles and 47% were adults. However, canaries 2, 3, and 4 originated from the same farm, where juvenile mortality reached 80% (4/5). Additionally, the beginning of mortality coincided with the introduction of an adult bird of the same species to the facility. Studies indicate that adult birds may not exhibit clinical signs while shedding a large number of infectious oocysts into the environment (Maslin and Latimer \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Although fecal oocyst testing was not performed on the introduced adult bird, it is possible that this individual served as the source of infection for the juveniles.\u003c/p\u003e \u003cp\u003eDepending on the host species and the stage of infection, the occurrence of histological lesions can vary significantly among organs. In the intestine, lesions may present with different patterns and localizations. Some animals exhibit enteritis with inflammatory infiltrates confined to the lamina propria, associated with necrosis and hemorrhage (Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Terio and Adkesson \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Others display transmural enteritis with intense lymphocytic infiltrates, resembling lymphoma (Cushing et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). In the present study, 8/10 great-billed seed finches exhibited transmural intestinal lesions predominantly in the duodenum and jejunum. These lesions were characterized by numerous lymphocytes and macrophages replacing crypts and villi, while lesions in other organs were scarce. As this is the first documented report of systemic isosporosis in great-billed seed finches, it is possible that this represents the most common presentation of the disease in this species. In green-winged saltators, systemic isosporosis typically affects the spleen, liver, and small intestine; however, lesions in the kidneys, heart, and lungs may also occur (Oliveira et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). In the present study, findings in the green-winged saltator (case 5) were consistent with changes in multiple organs, with a predominance in the small intestine, liver, spleen, and heart.\u003c/p\u003e \u003cp\u003eTo better characterize the pathogen in one of the birds (green-winged saltator), the mitochondrial cytochrome c oxidase subunit 1 (COI) gene was amplified and sequenced. This gene has been shown to be reliable for detecting a diverse range of \u003cem\u003eIsospora\u003c/em\u003e spp. sequences (Kubiski et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In this study, the sequenced sample exhibited over 99% identity with sequences of \u003cem\u003eIsospora\u003c/em\u003e spp. isolates from a purple honeycreeper (\u003cem\u003eCyanerpes caeruleus\u003c/em\u003e) at the San Diego Zoo (Kubiski et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This bird belongs to the family Thraupidae, the same family as the green-winged saltators, and it is native to Brazil, specifically to the western Amazon. Similar to other genera in the family Eimeriidae, parasites of the genus \u003cem\u003eIsospora\u003c/em\u003e spp. are known to exhibit host specificity (Schrenzel et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). However, interspecific transmission is possible in mixed-species environments (Kubiski et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Furthermore, experimental studies suggest that parasite species with life cycles restricted to the gastrointestinal tract are host-specific, whereas those with asexual stages that multiply in mononuclear cells as part of their life cycle exhibit unknown specificity (Box 1970). These findings may explain the genetic identity between the parasite in the present case and that of a different avian species. The genetic identity of 97.50% with \u003cem\u003eIsospora\u003c/em\u003e sp. from Brazil does not indicate that it is the same parasite species. Although the similarity threshold for the COI gene is not well defined, the 1% divergence in other genetic targets may suggest a different species of \u003cem\u003eIsospora\u003c/em\u003e. Based on the phylogenetic tree, a clear ancestral distance was observed between the our sample from green-winged saltator, and the other Brazilian isolate, indicating that they are probably distinct species.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe combination of gross and microscopic findings enabled the diagnosis of systemic isosporiasis in the birds of the present study. PCR and sequencing confirmed \u003cem\u003eIsospora\u003c/em\u003e sp. in green-winged saltator. This report is the first description of systemic isosporiasis in great-billed seed finches, characterized by severe enteritis that primarily affects the small intestine. The intestine and liver were the organs most frequently affected. The impact of this disease on wild populations of great-billed seed finches is still unknown; however, this report highlights the significance of the disease in captive populations. Histological changes in canaries and green-winged saltators are similar to those reported previously, with young canaries being possibly more susceptible.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of competing interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declared no conflicts of interest in relation to the research, authorship or publication of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCamila Issa Amaral:\u003c/strong\u003e Investigation, Data Curation,\u0026nbsp;Methodology,\u0026nbsp;Writing - Original Draft. \u003cstrong\u003eAyisa Rodrigues de Oliveira:\u003c/strong\u003e Methodology,\u0026nbsp;Writing - Review \u0026amp; Editing\u003cstrong\u003e\u0026nbsp;Eric Santos Oliveira:\u0026nbsp;\u003c/strong\u003eWriting - Review \u0026amp; Editing\u003cstrong\u003e\u0026nbsp;Marcelo Coelho Lopes:\u003c/strong\u003e Methodology, Writing - Review \u0026amp; Editing\u003cstrong\u003eMaira dos Santos Carneiro Lacerda\u003c/strong\u003e\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003eInvestigation, Writing - Review \u0026amp; Editing\u0026nbsp;\u003cstrong\u003eMarcelo Pires Nogueira de Carvalho:\u0026nbsp;\u003c/strong\u003eMethodology,\u0026nbsp;Writing - Review \u0026amp; Editing\u0026nbsp;\u003cstrong\u003eRoselene Ecco:\u003c/strong\u003e Investigation,\u0026nbsp;Supervision,\u0026nbsp;Writing - Review \u0026amp; Editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eR. Ecco was\u0026nbsp;supported by a fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnológico (National Council for Scientific and Technological Development),\u0026nbsp;C. I. Amaral, E.S. Oliveira, M. C. Lopes, M. S. C. Lacerda\u0026nbsp;were supported by the \u003cem\u003eCoordenação de Aperfeiçoamento de Pessoal de Nível Superior\u0026nbsp;\u003c/em\u003e(Coordination of Improvement of\u0026nbsp;Higher Education\u0026nbsp;Personnel), Brazil, Finance Code 001.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors confirm that the animals were treated with the veterinary standard of care according to specific requirements of our institution for ethics approval.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAdkesson MJ, Zdziarski JM, Little SE (2005). Atoxoplasmosis in tanagers. J Zoo Wildl Med 36:265–272 https://doi.org/10.1638/03-091.1 \u003c/li\u003e\n \u003cli\u003eBall SJ, Brown MA, Daszak P, Pittilo RM (1998). Atoxoplasma (Apicomplexa: Eimeriorina: Atoxoplasmatidae) in the greenfinch (Carduelis chloris). J Parasitol 84(4):813-7. \u003c/li\u003e\n \u003cli\u003eBirdLife International. Species factsheet: Sporophila maximiliani. Downloaded from http://datazone.birdlife.org/species/factsheet/great-billed-seed-finch-sporophila-maximiliani on 2023 Nov 16.\u003c/li\u003e\n \u003cli\u003eBrasil (2016) Sumário executivo—Livro Vermelho da Fauna Brasileira Ameaçada de Extinção.\u003c/li\u003e\n \u003cli\u003eCooper JE, Gschmeissner S, Greenwood AG (1989). Atoxoplasma in greenfinches (\u003cem\u003eCarduelis chloris\u003c/em\u003e) as a possible cause of ‘‘going light.’’ Vet Rec 124(5):343–344. https://doi.org/10.1136/vr.124.13.343 \u003c/li\u003e\n \u003cli\u003eCushing TL, Schat KA, States SL, Grodio JL, O'Connell PH, Buckles EL (2011). Characterization of the host response in systemic Isosporosis (Atoxoplasmosis) in a Colony of captive American goldfinches (\u003cem\u003eSpinus tristis\u003c/em\u003e) and house sparrows (\u003cem\u003ePasser domesticus\u003c/em\u003e). Vet Path 985:985–992. https://doi.org/10.1177/0300985810391114 \u003c/li\u003e\n \u003cli\u003eDestro GFG, Pimentel TL, Monti R, Sabaini RM, Borges RC, Barreto R (2012). Efforts to combat wild animals trafficking in Brazil. In: Lameed GA (ed) Biodiversity enrichment in a diverse world. Intech Open, London pp 33–36.\u003c/li\u003e\n \u003cli\u003eFlach EJ, Dodhia HS, Guthrie A, Blake DP (2022). Systemic isosporiasis (atoxoplasmosis) in passerine birds at the Zoological Society of London, London Zoo. J Zoo Wildl Med 53(1):70-82. https://doi.org/10.1638/2021-0087 \u003c/li\u003e\n \u003cli\u003eGill H, Paperna I (2008). Proliferative visceral Isospora (atoxoplasmosis) with morbid impact on the Israeli sparrow (\u003cem\u003ePasser domesticus\u003c/em\u003e biblicus Hartert, 1904). Parasitol Res 103(3):493–499 https://doi.org/10.1007/s00436-008-0986-4 \u003c/li\u003e\n \u003cli\u003eJamriška J, Lavilla LA, Thomasson A, Barbon AR, Lopéz JF, Modrý D (2013). Treatment of atoxoplasmosis in the Blue-crowned Laughing Thrush (\u003cem\u003eDryonastes courtoisi\u003c/em\u003e). Avian Pathol 42(6):569-571 https://doi.org/10.1080/03079457.2013.854309 \u003c/li\u003e\n \u003cli\u003eKhan RA, Desser SS (1971). Avian Lankesterella infections in Algonquin Park, Ontario. Can J Zool 49(8):1105–1110. DOI: https://doi.org/10.1139/z71-171 \u003c/li\u003e\n \u003cli\u003eLevine ND (1982). The genus Atoxoplasma (Protozoa, Apicomplexa). J Parasitol 68(4):719-723 https://doi.org/10.2307/3280933 \u003c/li\u003e\n \u003cli\u003eLindstrom KM, Dolnik O, Yabsley M, Hellgren O, O’Connor B, Parn H, Foufopoulos J (2009). Feather mites and internal parasites in small ground finches (Geospiza fuliginosa, Emberizidae) from the Galapagos Islands (Ecuador). J Parasitol 95(1):39–45 https://doi.org/10.1645/GE-1655.1 \u003c/li\u003e\n \u003cli\u003eLuna LG (1968). Manual of histologic staining methods of the Armed Forces Institute of Pathology, 3rd Edn. McGraw-Hill, New York.\u003c/li\u003e\n \u003cli\u003eMachado RB, Silveira LF, Gomes da Silva MIS, Ubaid FK, Medolago CA, Francisco MR, Dianese JC (2019). Reintroduction of songbirds from captivity: the case of the Great billed Seed finch (\u003cem\u003eSporophila maximiliani\u003c/em\u003e) in Brazil. Biodivers Conserv 29:1613–1636 https://doi.org/10.1007/s10531-019-01830-8 \u003c/li\u003e\n \u003cli\u003eMaslin WR, Latimer KS (2009). Atoxoplasmosis in canary fledglings: severe lymphocytic enteritis with preferential parasitism of B lymphocytes. Avian Dis 3:473-476 https://doi.org/10.1637/8557-121008-Case.1 \u003c/li\u003e\n \u003cli\u003eMcNamee P, Pennycott T, McConnel S (1995). Clinical and pathological changes associated with atoxoplasma in a captive bullfinch (\u003cem\u003ePyrrhula pyrrhula\u003c/em\u003e). Vet Rec 136(3):221–222 https://doi.org/10.1136/vr.136.9.221 \u003c/li\u003e\n \u003cli\u003eMiddleton AL, Julian RJ (1983). Lymphoproliferative disease in the American goldfinch, Carduelis tristis. J Wildl Dis 19(3):280-285 https://doi.org/10.7589/0090-3558-19.3.280 \u003c/li\u003e\n \u003cli\u003eMohr F, Betson M, Quintard B. Investigation of the presence of \u003cem\u003eAtoxoplasma\u003c/em\u003e spp (2017). in Blue-crowned Laughingthrush (\u003cem\u003eDryonastes courtoisi\u003c/em\u003e) adults and neonates. J Zoo Wildl Med 48(1):1–6 https://doi.org/10.1638/2016-0044.1 \u003c/li\u003e\n \u003cli\u003eMugridge NB, Morrison DA, Jäkel T, Heckeroth AR, Tenter AM, Johnson AM (2000). Effects of sequence alignment and structural domains of ribosomal DNA on phylogeny reconstruction for the protozoan family Sarcocystidae. Mol Biol Evol 17(12):1842-1853 https://doi.org/10.1093/oxfordjournals.molbev.a026285 \u003c/li\u003e\n \u003cli\u003eOliveira AR, Souza TD, Mol JPS, Flecher MC, Hiura E, Santos RL. Pathological and molecular characterization of systemic isosporosis (atoxoplasmosis) in captive green-winged saltator (\u003cem\u003eSaltator similis\u003c/em\u003e) (2018). Vet Parasitol May 15;255:98-101 https://doi.org/10.1016/j.vetpar.2018.04.007 \u003c/li\u003e\n \u003cli\u003ePartington CJ, Gardiner CH, Fritz D, Phillips LG, Montail RJ (1989). Atoxoplasmosis in Bali mynahs (\u003cem\u003eLeucospar rothschildi\u003c/em\u003e). J Zoo Wildl Med 20(3):328–335 https://doi.org/10.2307/41262613 \u003c/li\u003e\n \u003cli\u003ePennycott TW, Ross HM, McLaren IM, Park A, Hopkins GF, Foster G (1998). Causes of death of wild birds of the family Fringillidae in Britain. Vet Rec 143(3):155–158 https://doi.org/10.1136/vr.143.6.155 \u003c/li\u003e\n \u003cli\u003eQuiroga MI, Aleman N, Vazquez S, Nieto JM (2000). Diagnosis of atoxoplasmosis in a canary (\u003cem\u003eSerinus canarius\u003c/em\u003e) by histopathologic and ultrastructural examination. Avian Dis 44:465–469. \u003c/li\u003e\n \u003cli\u003eRossi G, Perrucci S, Taccini E, Vitali CG, Braca G, Renzoni G (1997). Mortality in black siskins (\u003cem\u003eCarduelis atrata\u003c/em\u003e) with systemic coccidiosis. J Wildl Dis 33(1):152-157 https://doi.org/10.7589/0090-3558-33.1.152\u003c/li\u003e\n \u003cli\u003eSánchez-Cordón PJ, Go´mez-Villamandos JC, Gutie´rrez J, Sierra MA, Pedrera M, Bautista MJ (2007). \u003cem\u003eAtoxoplasma\u003c/em\u003e spp. infection in captive canaries (\u003cem\u003eSerinus canaria\u003c/em\u003e). J Vet Med A Physiol Pathol Clin Med 54(1):23–26. https://doi.org/10.1111/j.1439-0442.2007.00909.x \u003c/li\u003e\n \u003cli\u003eSchrenzel MD, Maalouf GA, Gaffney PM, Tokarz D, Keener LL, McClure D, Griffey S, McAloose D, Rideout BA (2005). Molecular characterization of isosporoid coccidia (\u003cem\u003eIsospora\u003c/em\u003e and \u003cem\u003eAtoxoplasma\u003c/em\u003e spp.) in passerine birds. J Parasitol 91(3):635-647 https://doi.org/10.1645/GE-3310 \u003c/li\u003e\n \u003cli\u003eTerio KA, Adkesson MJ (2019). Systemic isosporosis in passerine birds. In: Miller ER, Lamberski N, Calle P (eds.). Fowler’s Zoo and Wild Animal Medicine, Elsevier, St. Louis (MO), pp 454–458.\u003c/li\u003e\n \u003cli\u003eBox ED (1975) Exogenous stages of \u003cem\u003eIsospora serini\u003c/em\u003e (Aragão) and \u003cem\u003eIsospora canaria\u003c/em\u003e sp. n. in the canary (\u003cem\u003eSerinus canarius\u003c/em\u003e Linnaeus). J Protozool 22(2):165-169 https://doi.org/10.1111/j.1550-7408.1975.tb05844.x \u003c/li\u003e\n \u003cli\u003evan Riper C 3rd, van Riper S, Laird M (1987) Discovery of Atoxoplasma in Hawaii. J Parasitol 73(5):1071-1073.\u003c/li\u003e\n \u003cli\u003eKubiski SV, Witte C, Burchell JA, Conradson D, Zmuda A, Barbon AR, Vilches-Moure JG, Felt SA, Rideout BA (2022). Mitochondrial Gene Diversity and Host Specificity of Isospora in Passerine Birds. Front Vet Sci 29;9:847030. https://doi.org/10.1111/10.3389/fvets.2022.847030\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"veterinary-research-communications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"verc","sideBox":"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)","snPcode":"11259","submissionUrl":"https://submission.nature.com/new-submission/11259/3","title":"Veterinary Research Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"atoxoplasmosis, birds, great-billed seed finch, histopathology, protozoa","lastPublishedDoi":"10.21203/rs.3.rs-6346858/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6346858/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSystemic isoporosis (atoxoplasmosis) is a disease caused by apicomplexan parasites of the genus \u003cem\u003eIsospora\u003c/em\u003e, with systemic distribution due to an extraintestinal part of the cycle. In this report we described the gross and histological lesions of systemic isosporosis in 15 passeriform birds from three different species: \u003cem\u003eSporophila maximiliani\u003c/em\u003e (great-billed seed finch), \u003cem\u003eSerinus canaria\u003c/em\u003e (island canary), and \u003cem\u003eSaltator similis\u003c/em\u003e (green-winged saltator), all captive birds originating from different properties in Minas Gerais, Brazil. Between 2017 and 2022, 15 passerines were sent to the Veterinary School of the Universidade Federal de Minas Gerais for post mortem examination, as well as fixed tissue samples for histopathological analysis. Histologically, the lamina propria of the small intestine in 13 out of 15 birds showed marked histiocytic and lymphoplasmacytic infiltrates with rare heterophils. Merozoites compatible with \u003cem\u003eIsospora\u003c/em\u003e spp. were observed within the cytoplasm of macrophages and extracellularly. Histological changes associated with merozoites were also seen in different organs like liver (9/15), lungs (4/15), heart (3/15), spleen (1/15), and skeletal muscle (1/15). To further characterize the pathogen, DNA was extracted from frozen tissues of one bird (\u003cem\u003eSaltator similis\u003c/em\u003e), and 23S large subunit ribosomal RNA and cytochrome c oxidase subunit 1 (COI) genes were amplified and sequenced. Systemic isosporosis affects various passerine species; however, this is the first report in \u003cem\u003eSporophila maximiliani\u003c/em\u003e. This study enabled the characterization and description of the histological lesions associated with systemic isosporosis in this species.\u003c/p\u003e","manuscriptTitle":"Systemic isosporosis in different species of passerine birds","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-05 06:28:08","doi":"10.21203/rs.3.rs-6346858/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-21T15:58:30+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-21T14:30:51+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-16T21:18:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-15T12:18:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"237436912610829850879624364266437093577","date":"2025-04-07T16:21:06+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-06T16:44:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"210750742732492174946741704299597803823","date":"2025-04-06T15:53:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"97853799011211318653397119986054307819","date":"2025-04-06T13:17:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"270492294438349764605122869414558288531","date":"2025-04-05T15:54:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"248414707514207310436176901525048869197","date":"2025-04-05T11:09:55+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-04T05:22:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-04-03T22:29:04+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-03T22:27:57+00:00","index":"","fulltext":""},{"type":"submitted","content":"Veterinary Research Communications","date":"2025-03-31T16:56:53+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"veterinary-research-communications","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"verc","sideBox":"Learn more about [Veterinary Research Communications](https://www.springer.com/journal/11259)","snPcode":"11259","submissionUrl":"https://submission.nature.com/new-submission/11259/3","title":"Veterinary Research Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"d4680f66-8543-4bea-ad95-d7bc57366c89","owner":[],"postedDate":"May 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-06-16T15:58:30+00:00","versionOfRecord":{"articleIdentity":"rs-6346858","link":"https://doi.org/10.1007/s11259-025-10785-x","journal":{"identity":"veterinary-research-communications","isVorOnly":false,"title":"Veterinary Research Communications"},"publishedOn":"2025-06-13 15:56:57","publishedOnDateReadable":"June 13th, 2025"},"versionCreatedAt":"2025-05-05 06:28:08","video":"","vorDoi":"10.1007/s11259-025-10785-x","vorDoiUrl":"https://doi.org/10.1007/s11259-025-10785-x","workflowStages":[]},"version":"v1","identity":"rs-6346858","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6346858","identity":"rs-6346858","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}